- At least 3 weeks must have passed since any of the following: systemic corticosteroids, immunotherapy (for example, T-cell infusions, immunomodulatory agents, interleukins, MCC vaccines, intravenous immunoglobulin, expanded polyclonal tumor infiltrating lymphocytes [TIL] or lymphokine-activated killer [LAK] therapy), pentoxifylline, other small molecule or chemotherapy cancer treatment, other investigational agents or other systemic agents that target Merkel cell carcinoma